1. Field of the Invention
The present invention relates to a semiconductor integrated circuit and to a method for testing the semiconductor integrated circuit.
2. Description of Related Art
A semiconductor integrated circuit is known. The semiconductor integrated circuit includes a semiconductor chip. The semiconductor chip includes a plurality of wiring layers and contacts (vias or contacts) for connecting the plurality of wiring layers. Additionally, in order to check whether or not resistance values of the contacts and the wirings are desirable, a chain structure is installed in the semiconductor chip. The chain structure includes wirings formed in the wiring layers, and the contacts for connecting them. For example, when a number of the wiring layers is three, a chain structure is formed of: a diffusion layer; a first layer wiring; a second layer wiring; a third layer wiring; a first via for connecting the first layer wiring to the diffusion layer; a second via for connecting the first layer wiring to the second layer wiring; and a third via for connecting the second layer wiring to the third layer wiring. The resistance value of the chain structure is measured to check the resistance values of the wirings and the contacts.
When checking the resistance values, it is required to identify a failed wiring layer or contact. For this reason, a plurality of chain structures are formed to correspond to the plurality of wiring layers. In order to check the resistance values of the respective chain structures, electrodes are provided on both ends of the respective chain structures. The resistance of the respective chain structures is measured by probing the electrodes.
On the other hand, in document 1 (Japanese patent publication JP-A-Heisei-6-216208), a unit for measuring a contact of an integrated circuit is disclosed, which has a plurality of contacts arranged to have an (m×n)-matrix shape on a substrate, m number of first layer wirings for connecting the contacts of the same row each other with wirings from one electrode side, and m number of second layer wirings for connecting the contacts of the same column each other with wirings from the other electrode side.
Furthermore, in document 2 (Japanese patent publication JP-A-2005-11970), a testing device for a conductor device is disclosed, which includes a switching transistor and a first resistor element. In the switching transistor, a gate is connected to a signal line, and one of a source and drain is connected to a first wiring. In the first resistor element, one terminal is connected to one of the source and drain included in the switching transistor, and another terminal is connected to a second wiring. The first resistor element includes at least one of a means for electrically connection.